Well reamer



March 7, 1933. I j CONANT 1,900,226

WELL REAMER Filed Jan. 2, 1932 2 Sheets-Sheet l March 7, 1933. j CONANT 1,900,226

WELL REAMER Filed Jan. 2, 1932 2 Sheets-Sheet 2 Patented Mar. 7, 1933 UNITED STATES PATENT OFFICE DAVID J. GONANT, OI MEMPHIS, TENNESSEE WELL BEAMEB,

Application filed January 2,- 1932. Serial No. 584,383.

This invention relates to improvements in tools for drilling wells and more particularly to reamers for use in connection therewith for the purpose of locally enlarging the well bore at a desired place or places.

,Artesian wells particularly for water supply are drilled through varied strata and into water bearing sand. A well casing is provided which extends through these varied strata and a strainer is secure to and projects below the lower end of the casing deep into if not entirely through the sand strata. Water must flow through this strainer from the sand and the openings in the strainer must be large enough to allow the water flow, yet fine enough to restrain the sand. Even so the openings are rapidly enlarged and the strainer must eventually be replaced or the well be abandoned.

As one way of overcoming these difficulties a bore much larger than the strainer used'has been made and the space around the strainer has been filled with ravel. In such case reliance is placed on t e gravel to restrain the sand and the openings in the strainer need only be small enough to prevent the gravel entering. Such gravel type of wells have not only largely increased the strainer life buthave also effected tremendous increases in well capacity, but it has been necessary to make, at large extra cost, and ordinaril to completely case at still greater cost, a ore from the surface of the ground downward which approximated the desired diameter of the grave section except that some enlar ement in the sand has been accomplished y washing the sand walls down. Unfortunately however, even then the resulting bore in the sand is uneven and cannot be satisfactorily controlled. It is the purpose of the present tool to cut, and control the size of, this larger bore thereby permitting the bore and casing through the overlying strata to be only sufliciently larger than the strainer and strainer pipe to be used to allow feeding in, or placing, of the gravel around the strainer after the strainer is in place.

The objects of the invention are to provide a cutting tool for well drilling that may be 50 passed down through the well bore or casing and expanded at any desired point to cut a larger diameter hole therebelow.

A further object is to provide a tool of this character in which the reaming blades may be retracted without withdrawing the tool within a casing and which tool may then be used for additional drilling at a smaller size and may again be enlarged at a lower de th to ream out an additional enlarged chamber or chambers without the necessity of following same up with a casing.

A further object of the invention is to provide fluid pressure means for opening up the blades of the reamer in such a device and means for holding the blades in opened position, and a still further object is to deliver water from the drill pipe past the reamer bit to the well drilling bit therebelow.

The means by which the foregoing and other objects are accomplished and the mannor of their accomplishment will readily be understood from the following specification on reference to the accompanying drawings in which Fig. 1 is a vertical section on the center line of the drill stem and the reamer bits showing the bits in closed position;

Fig. 2 is a section at right angles to Fig. 1, showing the bits in fully extended position;

Figs. 3, 4 and '5 are respectively transverse sections taken on the linesIII-III; IVIV and V--V of Fig. 1;

Fig.6 is a fr mentary sectional elevation showing a modi ed form of port;

Fig. 7 is a side elevation corresponding with Fig. 2; and

8, an elevation corresponding with Referring now to the drawings in which the various parts are indicated by numerals, 10 is the casing of a well, 11 is the well bore through clay or other overlying strata and 12 an enlarged chamber being reamed out in the sand.

The tool comprising essentially a head 14 which is screwed on to a drill pipe 15 which extends to the surface of the ground. The head 14 is transversely slotted at 16 to provide a pocket in which reamer blades 17 may be housed. In such retracted position the blades occupy the }position 17A. Adjacent the upper end of t e pocket is a pin 18 on which the blades 17 are pivoted, the holes for the pivot pin in the two blades being adcylinder is a compression spring 25 which acts to hold the piston and piston rod attached thereto in raisedposition. Adjacent the lowerend of the cylinder is a port 26 which establishes free communication be tween the interior of the cylinder and the surrounding well bore or casing. Adjacent the lower end of the piston rod 20 is a port 27 to which a passageway 28 leads from the top of the piston. Thebore 19 for the piston rod is also provided with a port 29, this'port and the piston rod port 27 being out of mg ister when the piston and rod are in raised position, but are brought into register when the piston and rod are fully depressed. The port 29 may discharge directly outward through the head but preferably is connectedby a pipe 30 with a're'entrant port 31 establishing a passageway from the port 29 into the lower end of the head.

32 is a drill bit which may be secured directly into the lower end of the head. Preferably however a tubular drill bar 33 is secured into the head and the drill bit 32 secured to the lower end of such bar. The length of the bar is adjusted to various conditions of drilling met with. The drill bit 32 is provided with ports 34 which lead from;-

a'passageway 35 extending from the top of the bit. The port 29 is thus brought into communication through the channelway 30, the port 31, the tubular bar 33, and the passageway 35 with the ports 34, so that water forced downward through the drill stem is discharged in proximity to the cutting edge of the bit 32 and well below the reamer blades 17. The piston rod 20 is also provided with a transverse notch or pocket 36 which is moved into register with a latch member when the piston 22 is fully depressed. This. latch member may comprise a ball 37, which is inwardly urged by a compression spring 38. The spring 38 is held in place by a threaded plug 39. The restraining action of this latch on the piston rod is made less than the thrust of the spring 25, so that the latter will definitely disengage the latch and force the piston upward.

,Pivotally connected to the blades 17, as by pins 40 are links il-one link being connected to each of the blades. The opposite ends of these links are both connected by a joint pin 42 to the lower end of the piston rod 20, the relation of the links e, the piston rod and the rearner blades ein such that when the piston is in raised positlon the In using the device the well is ordinarily bored through the underlying strata tothe surface or slightly into the water bearing sands and ordinarily cased .to such level. The drilling tools are then removed and the reamer head with the pilot drill is attached and lowered into the well. Durin such lowering the reamer blades are held oused within the head, by the action of the spring 25 against the underside of the piston. When the head has been lowered to desired position the drill stem andv if necessary the surrounding well bore, are filled with water, the bore however ordinarily being full of water from prior operation or ground conditions. At such time fluid pressure on the piston is balanced.

Rotation of the drill pipe and tools attached thereto is begun, and additional pressure is put. on the column of water in the drill pipe to overcome the spring pressure, force the piston downward and swing the reamer blades outward into cutting position, the full amount of such pressure being effective on the piston. As the piston reaches the end of this movement the blades extend outward at right angles to the head, the ports 27 and 29 come into register and the pressure is reduced by escape of the water through the piston rod and these ports. At the same time-however the'latch 37 engages the notch 36 establishing a resistance against return movement to compensate for such reduction in pressure. It will be understood that the cutting resistance exerted on the lower edge of the outer ends of the blades would in such instance also assist in holding the blades in extended position and would assist in completing the downward movement of the piston and rod and the accomplishment of the locking action. Thereafter drilling with the blades in extended or reaming position is continued to such depth in the sand as is-desired, an enlarged bore of uniform diameter being cut by reason of the rigidity of the structure. Water discharged through the iston rod and ports during this operation ows upward carrying with it the cuttings of the reamer. At the same time the pilot drill is boringfin advance of the reamer and establishing a bore to steady and center the reamer action.

In cutting through the sand it sometimes happens that an intermediate stratum is encountered such for instance as an indurated layer of sand approximating sandstone in hardness which it is undesirable to ream through. In such case the pressure on the column of water in the drill tube is reduced. The drill tube is raised to free the reamer blades from the bottom of the cut and the spring beneath the piston is allowed to overcome the resistance of the latch and'close the blades within the head. The drill stem is again lowered and boring resumed with the pilot bit, but without water being sup lied throu h the drill stem, though shou d the modiil ed form of passageway 29A be used, water under pressure insufiicient to com ress the spring, may be supplied for such rilling. After the stratum .has through and desirable sand is again encoun tered water pressure is a ain established, or raised, on the piston an the reaming cycle above described is reestablished.

Having described my invention, what I claim is:

1. In a well reamer a tubular drill stem, a slotted head carried thereby, a pair of reamer blades pivotally mounted in saidslot, a cylinder chambered out in said head above said slot and in communication with said stem, a restricted bore connecting said cylinder and slot, a piston within said cylinder, a compression spring within said cylinder acting to hold said iston in raised position, a piston rod secured to said piston and extending downward therefrom, through said bore, links pivotally secured to said piston rod and to said blades,fluid pressure means for depressing said piston, means for reducing said pressure on movement of said piston to depressed position, and means engaging said rod when fully depressed, to restrain'return movement thereof.

2. In a well reamer a tubular drill stem, a slotted head carried thereby, a pair of reamer blades pivotally mounted in said slot, a cylinder chambered out in said head above said slot and in communication with said stem, a piston within said cylinder, a compression spring within said cylinder acting to hold said piston in raised position, means linking said piston to said blades, whereby depression of said piston will extend said blades and raising of said iston retract them, fluid pressure means or depressing said piston, means for reducing said pressure on movement of said "piston to depressed position, and means engaging with said linking means on full depression of said piston, to restrain return movement thereo said means being less powerful than said spring.

3. In a well reamer a tubular drill stem, a slotted head carried thereby, a pair of reamer blades ivotally mounted in said slot, a cylinder c ambered out in said head above been passed said slot and in communication with said stem, a restricted bore connectin said cylinder and slot, a piston within said cylinder, a compression spring within said c lmder acting to hold said piston in raise position, a piston rod secured to said piston and extending downward therefrom, through saidbore, links pivotally secured to said piston rod and to said blades, fluid pressure means for depressing said piston, means for reducing said pressure on movement of said piston to depressed position, and co-timed means acting on said rod, to restrain return movement thereof.

4. In a well reamer a tubular drill stem, a slotted head carried thereby, a pair of reamer blades pivotally mounted in said slot, a cylinder chambered out in said head above said slot and in communication with said stem, a re stricted bore connecting said cylinder and slot, a piston within said cylinder, a compression spring within said cylinder acting to hold said piston in raised position, a piston rod secured to said piston and extending downward therefrom, through said bore, links pivotally secured to said piston rod and to said blades, fluid pressure means for depressing said piston, and means for engaging said piston rod in depressed position, to restrain return movement thereof, said means being less powerful than said spring.

5. In a well reamer a tubular drill stem a slotted head carried thereby, a pair of reamer blades pivotally mounted in said slot, said head being chambered to form a c linder and a piston rod bore leadingthere rom to said slot, said cylinder being in communication with said stem, a piston within said cylinder, and a piston rod in, said bore, a compression spring within said cylinder acting to hold said piston in raised position, means linking said piston rod and to said blades, fluid pressure means for depressing said piston and extending said blades, and means acting on said rod in depressed position to resist return pressure thereof, said restraining means being less powerful than said spring.

6. In a well drilling tool, a tubular drill stem, a head secured on the lower end thereof and a drill bit carried by the lower end of said head, said bit having a downwardly extending tubularrod,closed at its lower end and laterally orted above said end, said head bein chamred out to form a cylinder for said iston and guide bore for said rod, said cy der being in communication with said stem, said guide bore being ported, and said rod and guide ports registering on depression of said piston, a passageway establishing communication between said guide port and said drill passa eway, a compression spring within said cylin er normally holding said piston in raised position, and said ports out of communication; a ir of reamer blades pivotally mounted in said head, links connecting saidpiston rod to said reamer blades and effective to extend said blades on depression of said piston, said piston rod having a notch in a side thereof, and a spring urged plunger extending laterally inward through a wall of said head and engaging with said notch when said piston is fully depressed, the holding resistance of said plunger and notch being less powerful than said spring.

7. In a well reamer, a tubular drill stem, a:

head carried thereby, reamer blades pivotally mounted in said head, a piston having a downwardly extending tubular rod closed at its lower end, and laterally ported above said end, said head being chambered out to form a cylinder for said piston and guide bore for said rod, said cylinder being in communication with said stem, and said guide bore having a port, normally out of register with said rod port, said ports being registerable on depression of said piston, a compression spring within said cylinder normally holding said piston in raised position, and extending downward therefrom, links pivotally secured to said piston rod and to said reamer blades and Bfi QCtlVGYtO extend said blades on depression of said piston, apilot bit disposed below said head and carried therefrom, said bit having ports therein and a passageway extending from said guide bore port to said bit ports, whereby communication is established between said drill stem and said bit ports when said blades are moved to reaming position.

In testimony whereof I hereunto aifix my signature.

DAVID J. CONANT. 

